Preparation of a Novel Cross-Linked Polymer for Second-Order Nonlinear Optics

Abstract

A novel cross-linked pyroelectric polymer with pronounced second-order nonlinear optical properties has been prepared. A multistep synthesis with several selective transformations including a kinetic resolution (transesterification) with the highly enantioselective Candida antarctica lipase B, yielded the monomer 4‘‘-{(R)-(−)-2-[(10-acryloyloxy)decyl]oxy}-3-nitrophenyl 4-{4‘-[(11-acryloyloxy)undecyloxy]phenyl} benzoate A2c which displayed a ferroelectric chiral smectic C phase with large spontaneous polarization (175 nC/cm2). The monomer was poled and subsequently cross-linked by in-situ photopolymerization in the surface-stabilized ferroelectric liquid crystalline state. The cross-linked pyroelectric polymer exhibited an electro-optical coefficient (r 22 − r 12) of 15−35 pm/V.

<title>Photorefractivity in ferroelectric liquid crystals</title>

“…First, the majority of flcs have a small degree of electronic second-order nonlinear character, as measured by small electro-optic coefficients (~j) that are 1-2 orders of magnitude lower than their crystalline counterparts. 37 The few exceptions are flcs that utilize molecules with large hyperpolarizabilities aligned along the polar axis.25737Y38 Second, the rzz coefficient dominates the electronic electrooptic mechanism in flcs. In this tilted geometry, accessing rz would require the writing beams to be p-polarized where no photorefiactivity is observed.…”

Ferroelectric liquid crystalline elastomers, 1. Variation of network topology and orientation

“…IR spectra were recorded using a Jasco IR-Report 100 spectrometer or a Bruker IFS 48 FT-IR-spectrometer. GPC measurements were performed using a Waters Liquid Chromatograph (with UV detector) with a column combination of 10 3 Å (ultrastyrgel) and 10 4 Å (PL-gel). To get a homogeneous blend (P4) of copolysiloxane P1 and crosslinkable oligosiloxane PS 901.5 (ABCR, P n 4.35 as determined by GPC measurements against polystyrene standards) the two components were dissolved in CHCl 3 and the solvent was evaporated.…”

“…The value of the piezocoefficient in these systems is strongly dependent on the orientation and geometry of the smectic layers (bookshelf or chevron). High crosslinking densities in the systems result in solids that are no longer able to switch in electric a.c.-fields 8,9,10) . Our successful approach to create smectic-C* elastomers that show piezoelectric effects, too, starts with an orientation of photo-crosslinkable ferroelectric polymers in the electric field.…”

New Liquid Crystalline Methacrylate Polymers Containing 4-Methacryloyloxyphenoxy Group and 4'-((S)-(+)-2-Methylbutoxy)biphenyl-4-carboxyl Mesogenic Group: 1. Synthesis and Characterization of the Monomers

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